Uses

Tonka bean contains coumarin, which is used as a flavoring in foods and tobacco, as well as a fragrance in cosmetics.

Dosing

There is no clinical evidence to support a specific dosage of tonka bean.

Contraindications

Contraindications have not been determined.

Pregnancy/Lactation

Information regarding safety and efficacy in pregnancy and lactation is lacking. Avoid use.

Interactions

None well documented.

Adverse Reactions

If ingested in modest amounts, tonka beans do not produce any serious adverse reactions.

Toxicology

Little information is available.

Botany

Members of the genus Dipteryx are native to South America (Venezuela, Guyana, and Brazil), as typically large trees bearing single-seeded fruits about 3 to 5 cm in length. The fruit is dried with the seed removed. If not processed further, the fruit is sometimes known as “black beans.” The beans are macerated in rum and then air-dried, resulting in the formation of a crystalline deposit of coumarin making the seeds appear frosted.

Tonka beans are rounded at one end and bluntly pointed at the other. The bean is black and deeply wrinkled longitudinally, with a very fragrant odor and an aromatic, bitter taste. 1

History

Tonka beans contain coumarin, which is used in the food, cosmetic, and related industries to impart a pleasant fragrance to cakes, preserves, tobacco, soaps, and liqueurs. 2 , 3 The seeds are sometimes cured in rum. 4 However, according to the Food and Drug Administration ( Code of Federal Regulations ), food containing any coumarin as a constituent of tonka beans or tonka extracts is deemed impure. 5 Synthetic coumarin has, to some extent, replaced the natural product.

South American natives mix the seed paste with milk to make a thick, nutty-flavored beverage. Extracts of the plant have been used in traditional medicine as a tonic and to treat cramps and nausea. Seed extracts have been administered rectally for schistosomiasis in China. The fruit has also been said to have aphrodisiac properties.

Chemistry

Coumarin is present at 1% to 3% by weight of the fermented seed, but some strains may contain up to 10%. 2 , 3 , 6 Umbelliferone (7-hydroxycoumarin) has been isolated from the seed.

Tonka beans contain 25% fat containing unsaponifiable sitosterin and stigmasterin, and a larger amount of starch. 1 Coumarin has an odor reminiscent of vanillin. A number of related isoflavones have been isolated from the heartwood, including odoratin and dipteryxin. The bark exudes a resin that contains lupeol, betulin, and other minor components.

Crude extracts of callus and roots of D. odorata were analyzed by high-pressure liquid chromatography to detect and quantify isoflavone contents. The structures of 2 isoflavones were elucidated as 7-hydroxy-4′,6-dimethoxyisoflavone and 3′,7-dihydroxy-4′,6-dimethoxyisoflavone. The production of dry biomass of 7-hydroxy-4′,6-dimethoxyisoflavone in cultured callus was 4.12 mg/g, approximately 11-fold higher than the amount accumulated in roots of D. odorata wild-growing plants. 7

Purification of an ethyl acetate-soluble fraction of the methanol extract of the seeds of D. odorata using a quinone reductase induction assay to monitor fractionation led to the isolation of the following 11 compounds: dipeteryxic acid, 5 methoxyxanthocercin A, isoliquiritigenin, 6,4′-dihydroxy-3′-methoxyaurone, sulfuretin, balanophonin, butin, eriodictyol, 7-hydroxychromone, 7,3′-dihydroxy-8,4′-dimethoxyisoflavone, and (−)-lariciresinol. 8

Uses and Pharmacology

There are no well-controlled studies describing the pharmacologic effects of tonka beans or their components. Coumarin is toxic when ingested in high doses.

Synthetic coumarin has been developed to replace the natural product in some cases. Warfarin (eg, Coumadin ), a substituted coumarin, is a potent anticoagulant used in human therapeutics and rodenticides. 9 , 10

Compounds isolated from the tonka bean have been studied in cancer chemoprevention and for acaricidal activity.

Clinical data

Research reveals no clinical data regarding the use of tonka beans for any condition.

Quinone reductase activity was induced in a dose-dependent manner in the concentration range of 2 to 30 mcM, with a maximum of 7-fold induction at the highest concentration tested. 11

Quinone reductase elevation with in vitro and in vivo systems correlates with induction of other protective phase 2 enzymes and provides a reasonable biomarker for the potential chemoprotective effect of test agents against cancer initiation.

In another study, the potential of all identified isolates to induce quinone reductase activity of Hepa 1c1c7 cells were evaluated. Isoliquiritigenin exhibited the most potent quinone reductase activity. 6,4′-Dihydroxy-3′-methoxyaurone, sulfuretin, and balanophonin also induced quinone reductase activity. 11

Acaricidal activityAnimal data

A cyclohexane extract of tonka beans was toxic to the common pyroglyphid house dust mite Dermatophagoides pteronyssinies , showing a dose-dependent acaricidal effect. Coumarin was identified as the active component.

After 24 hours, the median effective dose for coumarin 0.032 g/m 2 was very similar to that of benzyl benzoate 0.025 g/m 2 , a well-known and widely used acaricidal product. 12

Dosage

There is no clinical evidence to support a specific dosage of tonka bean.

Pregnancy/Lactation

Information regarding safety and efficacy in pregnancy and lactation is lacking. Avoid use.

Interactions

None well documented.

Adverse Reactions

If ingested in modest amounts, tonka beans do not produce any serious adverse reactions.

Toxicology

Dietary feeding of coumarin to rats and dogs has been associated with extensive hepatic damage, growth retardation, and testicular atrophy. 2 Large oral doses of the fluid extract may result in cardiac paralysis. 2 The median lethal dose (oral) of coumarin is 680 mg/kg in rats and 202 mg/kg in guinea pigs. 13

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